Greetings in that Divine and Most Precious Name of Our Lord and Savior Jesus Christ!
but I am having problems with what I see as the triumphalism of some Orthodox and how this can be reconciled with the other 25000 Christian denominations.
The simple answer, they can't be. Protestantism/Pentecostalism (and I say this having been raised a sincere and active Missionary Baptism and all the baggage it implies) is by definition a self-directed, splinter movement, which inherently is centrifugal rather than unifying. It is not us, its them. Orthodox is not the one making divisions and continual distinctions, we follow ONE form of Christian tradition uniformly across 2000 years with very little change or evolution aside from what is pragmatic. Our Christianity is not an obstacle it is simply a continuation of the original Christianity. Protestantism on the other hand, is not guided by adherence to continuity or tradition more so individualism and the power of personalities. It is by this nature sectarian and divisive, as human personalities are fickle and changing. This is precisely why Jesus Christ did not found the Church on personalities of the Apostles, but of the Apostolic work itself (ie, the Seven Sacraments and the Holy Tradition). The Church changes Christians, Christians do not necessarily have any need to change the Church. This is why there is an irreconcilable gulf between the endless groups of denominational Christianity and with Orthodox.
This should not discredit the sincerity of many Protestants, and we Orthodox have a lot to learn about charity, social service, and community outreach from our Protestant brothers and sisters, but from an Orthodox perspective, Protestantism is doomed to failure because it rejects the Divine Institution of the Seven Sacraments/Mysteries and so is not [part of the New Covenant relationship with God the Father which is through found at its highest form in participation of the Mysteries. The way the Apostle Paul explains it, the luncheons, charitable works, and good spirited fellowship of the Protestants are sufficient disciplines for "an expression of wisdom in a willful ritual, humility and asceticism, but are not of any value toward the surfeiting of the flesh." (Colossians 2:23) That is, the spiritual activities of the Protestant churches are great opportunities for voluntary service (willful ritual), charitable living (humility), and self controlled behavior (asceticism) but these things of and by themselves can do absolutely nothing for saving the flesh from sin, which is salvation in Christ Jesus. Orthodox teaches that these things are all good for humanity, but true salvation and real life can only be found through the Seven Sacraments/Mysteries combined with these kinds of living. Then, can humanity find real salvation, and only then. This is the inreconciable gap, because most Protestant churches by definition reject the Divinity of the Sacraments instead claiming them as mere symbols and almost empty rituals, thus they openly reject their salvation (what a shame in my heart and tears this brings me to meditate on

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I have gone to some "Cathecumen Classes" and it is more like a Protestant Recovery group than an actual class with educational material and learning involved. 90% of the time is spent bashing Protestants and their music and their lack of incense and lack of history. It is VERY discouraging . . .
That is unfortunate really, and I think the best advice has already been given here, that you should seek another Orthodox parish that is centered on different circumstances and will be more friendly to your own needs. God has many parishes in the world, because we humans have many different needs, and the Church can fulfill them all, its just a matter of being in the right place at the right time. It is prayer and faith and accepting God's open-door opportunities that bring us to these right places and times where and whenever they are. That being said:
I would like to read and study the Bible more but now I distrust the Bible as it seems all the translations are based on the translators Church affiliations.
Please Please Please by all means necessary, keep reading the Bible, particularly the Gospel. In fact, if you feel this way, ignore the historical and cultural baggage of linguistics and doctrines and theologies and canons and rules and laws and blah blah woof woof.
Just read the Gospels in any translation or version that sings to your heart, and read those red-letter words of Jesus with the sincerity of spirit as if Jesus Christ was there in the room speaking to you. Don't use your mental imagination as if you were reading a novel, instead, read the Gospels alone with your heart as if your were looking through a dear family photo album..
Stay Blessed,
Habte Selassie